diff --git a/packages/core/integration-tests/test/integration/webextension-mv3/manifest.json b/packages/core/integration-tests/test/integration/webextension-mv3/manifest.json
index 25e0fbf95c0..b8ff5f08993 100644
--- a/packages/core/integration-tests/test/integration/webextension-mv3/manifest.json
+++ b/packages/core/integration-tests/test/integration/webextension-mv3/manifest.json
@@ -12,7 +12,8 @@
   ],
   "content_scripts": [{
     "matches": ["https://*.google.com/*"],
-    "js": ["other-content-script.js"]
+    "js": ["other-content-script.js"],
+    "world": "ISOLATED"
   }],
   "action": {
     "default_popup": "popup.html"
diff --git a/packages/transformers/webextension/src/schema.js b/packages/transformers/webextension/src/schema.js
index 89534b91954..20f6dc6ca08 100644
--- a/packages/transformers/webextension/src/schema.js
+++ b/packages/transformers/webextension/src/schema.js
@@ -185,6 +185,10 @@ const commonProps = {
           enum: ['document_idle', 'document_start', 'document_end'],
         },
         all_frames: boolean,
+        world: {
+          type: 'string',
+          enum: ['ISOLATED', 'MAIN'],
+        },
       },
       additionalProperties: false,
       required: ['matches'],